This invention relates generally to the field of well production and the collection and processing of well fluids. Specifically, it relates to fluid collection systems to achieve the collection of produced gas from wells, which may be especially applicable to collection systems for methane gas. More particularly, the invention may relate to well gas collection systems for a plurality of wells, facilitating the flow and merging of gas from multiple well sources, directing entry of fluid into the collection system, and the processing of produced fluids into liquid and gas phases, potentially for subsequent collection and processing. The invention may be particularly applicable for well header systems, potentially relative to resource recovery for oil and gas, coal, and landfill applications.
The technology of the collection and processing of well fluids has undergone many conceptual changes, especially in the industries of resource recovery such as the oil and gas industries and the coal industry. The collection of gas as the primary or target resource or as a secondary or by-product of other resource development has increasingly become important in various fuel-dependent markets. The collection of gas has further served to address environmental concerns arising from the direct or indirect production of gas, especially in developing areas such as coal production and landfill operations.
Fluid collection systems for many of these operations have historically taken a variety of forms dependent upon, generally, the resource to be collected, and the nature of the subsequent processing or the use to which the collected resource is to be applied. Traditional forms of fluid collection systems may have incorporated elements from various fields, such as header systems, fluid inlets and outlets and the corresponding piping thereof, or the like, with varying results.
The coal industry in particular has utilized and developed gas collection systems for the collection and subsequent separation of produced well fluids. Wells may be installed in the respective coal field and may serve several purposes. The wells may be set for the primary purpose of producing methane gas. The methane gas may also be collected as a secondary or by-product result of coal production. The methane gas that can naturally occur within a coal field could be considered detrimental to the environment, especially as a contributor to the reduction in ozone layer, among other effects, particularly during the commercial development of the field. Additionally, a build-up of methane gas as a result of coal production may create health and general safety hazards to the surrounding environment and populous.
Raw methane gas produced from such wells may typically include water vapor entrained within the produced fluid. Water vapor may impair or serve as a detriment to the subsequent processing and transportation of methane gas. A need, therefore, exists for the collection of the produced methane gas and the separation of the gas from entrained water vapor.
Typical designs of collection systems in the coal industry may include header systems for the collection of produced well fluids from coal beds. Past attempts for the design of header systems for the collection of methane gas may have particularly provided a cylindrical header disposed at a particular configuration relative to ground surface. One such design may even provide a header disposed at a forty-five degree angle from the ground surface. Fluid production pipes from separate wells may connect the coal bed wells to the header, thereby providing a flow path from the producing wells to the header. Fluid from each well may enter the header through the respective production pipe and may separate in the header potentially due at least in part to the angled configuration of the header and the force of gravity upon the water vapor as the produced well fluid collects in the header. Water vapor entrained in gas from the wells may collect at the bottom of the header while methane gas separated from the water vapor may rise to an upper portion thereof. The separated gas can be subsequently transported, stored or processed accordingly. However, past attempts at methane collection and processing may have suffered from a lack of fully efficient water vapor separation, potentially at the initial step of fluid entry and collection in the header. Water vapor in past systems may not have adequately and appreciably separated from the collected methane gas. The collected gas may not be easily transported or processed due to the content of water vapor remaining entrained with the collected gas. A particular need existed, therefore, for collection systems that served more efficient gas separation roles than past attempts.
One attempt to increase the efficiency of systems collecting methane coal gas from multiple wells may have been disclosed in U.S. Pat. No. 6,119,711 issued to Dougherty, hereby incorporated by reference. The system of U.S. Pat. No. 6,119,711 may provide a header system providing pipes each leading from separate wells and mounted to a header. The pipes may be directly welded to the header and may be welded at an orientation divergent or transverse to the central portion or axis of the header or a radius thereof. The system may further provide the header in an upright orientation and a paired orientation of pipes each leading into one side of the header. The pipes may be arranged in a plurality of horizontal pairs so as to introduce gas from each pipe into the header. The gas may then flow into the opposite side of the header and may even provide individual fluid flows from each pipe to flow into a corresponding flow from the second of the paired pipes to potentially achieve some amount of gas and water vapor separation within the header, potentially in conjunction with a baffle plate. The system of U.S. Pat. No. 6,119,711, however, may suffer from several drawbacks that may ultimately affect the efficiency, structural integrity and convenience of the system.
One drawback of the header system of U.S. Pat. No. 6,119,711 concerns the potential efficiency of gas separation from entrained water vapor. The header system may rely upon the paired flow of gases from paired pipes to not only flow into an opposite side of the header, but for each flow from each pipe to potentially flow into the corresponding paired pipe flow to achieve some water vapor separation. The potential reliance upon paired flows of gas could affect the efficiency of the system, for example in potentially uneven flow environments between and among various wells, potentially as between paired pipes, and may produce an unintended, mechanically cumbersome design. Such attempt, therefore, may have failed to address the efficiency concerns identified in previous attempts at methane gas collection.
Furthermore, a particular need may exist in the field of methane coal gas collection for systems that are structurally and configurationally acceptable for field applications. The system of U.S. Pat. No. 6,119,711 may not have addressed potential structural and design limitations that may be commonplace in methane coal gas collection. Current header systems may typically provide a welded connection between pipes and the header. The type and configuration of the weld between pipes and the header may, in part, determine the structural integrity of the pipes and header, and potentially that of the entire system. U.S. Pat. No. 6,119,711 provides piping mounted to the header and a welded connection between the pipes and the header. The configuration of the pipes with respect to the header provide a pipe configuration divergent or transverse from the central portion or axis of the cylindrical header or a radius thereof. This type of pipe and header configuration may provide a mounting of the pipe that is less structurally robust than other potential configurations. Furthermore, the pipe and header configuration and resulting mounting may detrimentally affect the structural integrity of the header itself, as a larger inlet may be needed to accommodate the configuration and entry of the pipe. The gas pressures within the system may create a breach in the structural integrity of the pipe mounting. Well pressures at the inlet of typical header systems for methane coal gas collection may be 90 lbs. per square inch or more. Furthermore, current methane coal gas collection systems may potentially include compressors or other mechanical means of drawing well fluid through the collection system, typically inducing about 5 lbs. per square inch or more of pull on the system. The added pressure changes and resulting stress on the collection system may create a cracking or other like stress effects on the pipe-to-header mounting, especially for welded connections, or in the header itself that may detrimentally impair system integrity.
U.S. Pat. No. 6,119,711, while attempting to address gas separation efficiency characteristics potentially lacking in previous systems, may not have otherwise addressed potential system configurations desirable in the field. One example of the typical constraints on methane coal gas collection systems are the structures that may house the collection systems at the collection site. These structures may provide an efficient and protective enclosure for the system. The structure for the system may, however, potentially limit possible configurations for the collection system, particularly with regard to pipe and header configurations. Therefore, a long felt but unsatisfied need may have existed for gas collection systems having configurations suitable for particular collection cites while providing structural and efficiency characteristics lacking in previous gas collection systems. The system of U.S. Pat. No. 6,119,711, developed to potentially address the gas separation inefficiencies of previous systems, may actually teach away from the desired characteristics of a structurally and configurationally acceptable collection system.
Other attempts in various fields have produced a wide range of systems of gas collection. Previous attempts in various fields may be found in U.S. Pat. No. 3,789,588, issued to Laubli, U.S. Pat. Nos. 5,882,383, 5,753,013 and 5,554,209 issued to Dingfelder, U.S. Pat. No. 5,775,442 issued to Speed, U.S. Pat. No. 4,369,049 issued to Heath, U.S. Pat. No. 4,268,277 issued to Rooker, U.S. Pat. No. 4,214,883 issued to Raseley et al., U.S. Pat. No. 3,957,465 issued to Pircon, U.S. Pat. No. 3,877,904 issued to Lowrie, U.S. Pat. No. 3,331,188 issued to Sinex, U.S. Pat. No. 3,303,621 issued to Hill, U.S. Pat. No. 2,157,829 issued to Metzgar, and 864,158 issued to De Lany, each hereby incorporated by reference. However, each of these attempts may suffer, generally, from various deficiencies in separation efficiency, structural integrity and configuration desirability that may have been previously identified in the field of gas collection, especially for methane coal gas applications, and may have been developed without the particular needs and desired characteristics being considered for methane coal gas applications, generally. Many of the characteristics desirable for methane coal gas collection may have been theretofore unforeseen by those in the various fields.
The present invention is designed to address the potential problems associated with conventional gas collection systems. Accordingly, embodiments of the present invention may provide for well gas collection systems and methods of well gas collection that may address inadequacies of previous techniques. The invention may comprise, according to particular embodiments, a well gas collection system and methods of well gas collection whereby efficiency, structural integrity, and convenient application of the system may be more easily and adequately accomplished. The invention may comprise, in preferred embodiments, a well gas collection system and methods of well gas collection whereby the system may be accomplished with adequate gas separation efficiency, while retaining structural integrity and providing for convenient system configurations for field applications, particularly with regard to methane coal gas applications.
In addition, embodiments of the present invention may provide for gas collection systems directed to the collection of well gas from a plurality of wells, and in preferred embodiments, systems directed to well gas collection from a plurality of wells producing from coal beds. Embodiments may provide for applications directed to providing the merging of fluid flow into a gas collection element and inlets comprising merged fluidic flow paths to a collection element. Further, the present invention may comprise embodiments particularly directed to applications of gas separation incorporating various gas separation elements, potentially including baffle applications, among others. Particular embodiments may provide a baffle element equally responsive to inlets of a gas collection element and at least partially obstructing well fluid flowing into the gas collection element. The embodiments of the present invention may further provide for the flowing of well fluid substantially radially into a gas collection element of the system and inlet elements substantially coincident with a radius of the gas collection element. Embodiments of the present invention, therefore, may be considered developments away from previous efforts of well gas collection systems and methods of well gas collection, both generally and as more particularly described below.
In accordance with preferred embodiments, the present invention may provide a multiple well header system, comprising a header element having an upper end and a lower end and a sidewall connecting the upper end and the lower end, wherein the upper and lower ends and the sidewall form an interior chamber of the header element; a plurality of inlets in fluidic communication with the interior chamber through the sidewall; a plurality of inlet pipes each fluidically connected to one of the inlets and in fluidic communication with the interior chamber; a plurality of gas source pipes each fluidically connected to one of the inlet pipes and in fluidic communication with the interior chamber; and a gas outlet positioned through the header element in fluidic communication with the interior chamber; wherein each inlet pipe comprises a merged fluidic flow path in fluidic communication with the interior chamber.
Additional preferred embodiments of the present invention may further provide a multiple well header system, comprising a header element having an upper end and a lower end and a sidewall connecting the upper end and the lower end, wherein the upper and lower ends and the sidewall form an interior chamber of the header element; a plurality of inlets in fluidic communication with the interior chamber through the sidewall; a plurality of inlet pipes each fluidically connected to one of the inlets and in fluidic communication with the interior chamber, wherein a longitudinal axis of each inlet pipe is substantially coincident with a radius of the header element; a plurality of gas source pipes each fluidically connected to one of the inlet pipes and in fluidic communication with the interior chamber; and a gas outlet positioned through the header element in fluidic communication with the interior chamber.
Preferred embodiments may also provide a multiple well header system, comprising a header element having an upper end and a lower end and a sidewall connecting the upper end and the lower end, wherein the upper and lower ends and the sidewall form an interior chamber of the header element; a plurality of inlets positioned through the sidewall and in fluidic communication with the interior chamber; a baffle element within the interior chamber positioned in an orientation corresponding to the plurality of inlets wherein the baffle element is equally responsive to the inlets; a plurality of inlet pipes, each inlet pipe in fluidic communication with the interior chamber through fluidic connection to one of the plurality of inlets; a plurality of gas source pipes each fluidically connected to one of the inlet pipes; and a gas outlet positioned through a upper end of the header in fluidic communication with the interior chamber.
One object of the present invention, therefore, is to provide well gas collection systems, in various embodiments, employing desirable characteristics such as efficiency of gas separation, and in accordance with preferred objects of the invention, efficiency for gas separation in methane coal gas applications. Therefore, one goal of the present invention is to provide a well gas collection system that may achieve desirable levels of gas separation efficiency without sacrificing other desirable aspects of the present invention. One particular goal of the present invention, therefore, is the provision of a well gas collection system that incorporates novel features to accomplish levels of efficiency long identified as needed in methane coal gas collection but potentially heretofore inadequately addressed in the respective field.
Another object of the present invention is to provide well gas collection systems, in various embodiments, utilizing configurations and techniques that may achieve desired levels of structural integrity, and in accordance with preferred objects of the invention, levels of structural integrity in methane coal gas applications. A goal of the present invention, therefore, is to provide well gas collection systems incorporating robust configurations and techniques that may achieve greater levels of structural integrity as compared to conventional well gas collection systems. Another goal, therefore, is to provide well gas collection system configurations that allow for minimal cracking or other stress effects, or the like, of the system to achieve system integrity. Additionally, another goal of the present invention is to provide, in particular embodiments, well gas collection systems having configurations allowing for pipe-to-header connections, and, among others, in preferred embodiments, pipe-to-header welds and header thicknesses that provide structural system integrity, or the like, during well gas collection.
Furthermore, an object of the invention is to provide well gas collection systems, in various embodiments, allowing for convenient application of the system, and in accordance with preferred objects of the invention, levels of desirable convenience in methane coal gas applications. One goal of the present invention, therefore, is directed to system configurations and techniques that may be directed to particular field applications, and, among others, in accordance with preferred embodiments of the present invention, methane coal gas applications.
Other objects of the invention are disclosed throughout other areas of the specification and claims. In addition, the goals and objectives may apply either in dependent or independent fashion to a variety of other goals and objectives in a variety of embodiments. Additionally, the description and drawings that follow highlight the recited objectives and goals mentioned above, describing and depicting several embodiments of the present invention.